The harp, and I don't care what size. I've had a clarsach (or however you spell it) for 25+ years - 23 wire strings - but in my intermittent attempts to learn to play, I can never get past the fumble-fingered bit. And there's the rub, with any instrument - the first 10% and the last 10%. Getting out of "can't play anything" and getting to... professional standard, I suppose. The 80% in between is the easy bit. I maybe made 91% on guitar once upon a time, I've never made 9.1% on the harp!